Table 1 shows one common power train related problems of the 2012 GMC Sierra 3500.
| Problem Category | Number of Problems |
|---|---|
| Power Train problems |
The vehicle will not shift properly when towing a trailer. While going up a hill, the transmission will not downshift properly. While going downhill, the vehicle downshifts to 2nd gear while going 60 mph. I have contacted gm several times (they have it on file) that there is a problem with the transmission. They understand but said that they cannot do anything about it. This has been happening since it was brand new. Over and over again.
While driving on highway, transmission shifts hard to higher gear. Mthis started all of a sudden will take to dealership.
While pulling my fifth wheel trailer 12500# at highway speed 65 mph pulling a grade the check engine light came on and the reduced engine power message appeared on the dash. This reduced and limited the speed to 50 mph and steps the truck down from there until you can only do 20 mph on the interstate. This issue has happened three times in three months.